This invention relates in general to testing of electronic modules and in particular to detection of shorted output pins on an inertial sensor package.
Electronic brake control systems for vehicles are becoming increasing sophisticated. Such braking systems usually include an Anti-Lock Brake System (ABS) and a Traction Control (TIC) System. Additionally, a Vehicle Stability Control (VSC) System may be provided. A VSC System typically monitors vehicle motion parameters and is operable to selectively activate the vehicle wheel brakes and/or modify engine performance to avoid potential unwanted vehicle motions, such as, for example, a vehicle roll-over. A plurality of motion sensors, such as accelerometers and angular rate sensors are utilized to sense vehicle motion. The signals generated by the motion sensor elements are typically modified by a signal conditioning circuit and then provided to a microprocessor in an Electronic Control Unit (ECU) of the electronic brake control system. The ECU microprocessor utilizes a stored algorithm to monitor the vehicle motion parameters, and, upon detecting a potential vehicle stability problem, the microprocessor initiates corrective action.
The motion sensors are typically packaged with supporting circuitry, with the package containing one or more accelerometers and/or one or more angular rate sensors. The sensor packages may also include signal conditioning circuitry. Key to successful operation of the VSC system is proper functioning of the motion sensors and signal conditioning circuitry. Typically, the output pins for the motion sensors are physically located to next to one another. Thus, there is a potential for the output pins to short out, either internally or externally. If the pins are shorted, an output signal will continue to be produced, but the output signal would be inaccurate. Accordingly, sensor modules are tested prior to installation in a vehicle subsystem and subjected to further testing with Built In Tests (BIT's) during operation subsequent to installation for potential output pin shorting. However, such BIT's may be limited. Therefore, it would be desirable to provide additional testing to assure that the output pins have not been shorted together.